Dealing with Identical Users in the system

Well you got the virtual domain working, but in a practical environment there are times when you have identical users. For example, you have two users named John Doe, one logs in as john and the other logs in as doe.

Analyze this carefully! When you first created the users (John & Doe), by default they belong to the physical host netcontrol.org. But I will assume that john will receive email from the virtual domain “onetraining.net” and Doe will receive emails from netcontrol.org; therefore I will only include john in the virtual_maps file.
The real name may be the same: John Doe, but it has nothing to do with the account name. Note that they are a different physical identity

Insert your appropriate network in here. Make sure not to include relays to the public. If you are having difficulties getting out from your local area network to the outside world; check these settings. Most likely the problem is here.

Note: Perhaps you will see localhost in this trust and relay control section, if you can't sent emails comment the line and try again.